Real-time relighting previews with virtual light fields

In this paper, a real-time dynamic virtual light field algorithm is proposed that handles dynamic scenes. This algorithm can be used to generate real-time previews of relit diffuse scenes. The technique takes scene occlusions into account, which results in the realistic rendering of area shadows, diffuse interreflection and indirect shadows. To achieve real-time performance, the virtual light field is constructed on the GPU, rendering multiple layers of depth in a single pass. An important contribution of this paper is a technique to perform bounded retracing of a virtual light field. This allows dynamic objects to alter the flow of light in a scene, without requiring recalculation of the whole global illumination solution. Realistic global illumination effects are achieved in real-time, for scenes consisting of ten thousands of polygons, on consumer graphics hardware. Aside from the obvious applications in computer games, this algorithm can, when combined with existing inverse rendering algorithms, give a good approximation of what a scene will look like under different lighting conditions. This can give movie directors immediate feedback of how post-production relighting will affect the end result of their work.